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Aspects of krill growth and condition during late winter-early spring off East Antarctica (110-130°E)

journal contribution
posted on 2023-05-17, 10:52 authored by O'Brien, CJ, Patti VirtuePatti Virtue, Kawaguchi, S, Peter NicholsPeter Nichols
Antarctickrill, Euphausiasuperba, isakeystonespeciesintheSouthernOcean.However,informationon growth,dietandconditionduringwinterandearlyspringislimited,hamperingourunderstandingof these fundamentalbiologicalparametersatthisimportantperiodintheirlifecycle.Ourstudyassessed diet andconditionoflarvalandpostlarvalkrillcollectedfromopenwaterandbelowtheiceoffEast Antarctica(110–130% o E) inSeptember/October2007.Conditionwasassessedusinglipidcontent,growth ratesanddigestiveglandsize;feedinghistorywasassessedusingfattyacidprofilesandstomachcontent analysis;anda207-daystarvationstudyinvestigatedtheresponseofkrilltolong-termfooddeprivation. Potentialfooditems(Calanuspropinquus and sea-icebiota)wereanalysedforlipidandfattyacid compositiontocomparewithkrillsamples.Krillwerefoundtobeingoodcondition,withmeangrowth rate of0.95%permoultforpostlarvaeand14.79%forlarvae,andmeanlipidcontentof24.1%forpostlarvae and 6.6%forlarvae.Fattyacidprofilesandstomachcontentanalysisrevealedtwomainfeedingstrategies - krillbelowtheicewerefeedingmostlyonsea-icediatoms,whilethoseinopenwaterwereingesting copepodsanddetritus.Krillbelowtheicehadlargerdigestiveglandsthanthoseinopenwater.Furciliae fatty acidprofilesindicatedadietofheterotrophicflagellatesand/ordetritus.Postlarvalkrillsurvived207 days offooddeprivationbyusingbodyproteinandlipidreservesforenergy.Incontrast,krillfurciliae were severelydepletedafterjust5daysoffooddeprivation,indicatingthattheymustfeedcontinuallyat this timeofyear.Krill,copepodsandsea-icebiotawerealllowinpolyunsaturatedfattyacids,indicating that krillmustrelyonlaterspringphytoplanktonbloomstoobtaintheseessentialnutrientsrequiredfor reproduction.

History

Publication title

Deep-Sea Research. Part 2: Topical Studies in Oceanography

Volume

58

Issue

9-10

Pagination

1211-1221

ISSN

0967-0645

Department/School

Institute for Marine and Antarctic Studies

Publisher

Pergamon-Elsevier Science Ltd

Place of publication

The Boulevard, Langford Lane, Kidlington, Oxford, England, Ox5 1Gb

Rights statement

The definitive version is available at http://www.sciencedirect.com

Repository Status

  • Restricted

Socio-economic Objectives

Biodiversity in Antarctic and Southern Ocean environments